Pimpama-Coomera dual reticulation end use study: pre-commission baseline, context and post-commission end use prediction

Abstract

The Gold Coast Water Pimpama Coomera dual reticulation schemes' recycled water supply will be online in late 2009. In an attempt to achieve better estimates on both potable and likely recycled water end uses within this region, this paper presents a predictive model that utilises a range of input parameters, including: current use in the Gold Coast and the Pimpama Coomera regions at both a bulk billing and end use level; recycled water use at other dual reticulated schemes; and questionnaire survey of residents water source preferences for outdoor uses. Prior to the commissioning of recycled water, potable water is supplied through the recycled water pipelines. Water end use consumption analysis from the recycled water smart meter indicates that this supply source currently provides 20% of total household use with the majority of use being for toilet flushing. However, a range of factors have attributed to this low baseline level with evidence collected in this study indicating that higher recycled water consumption rates will occur once this supply line has been commissioned; largely due to the lower cost and fewer restrictions placed on this water source for discretionary outdoor purposes. The weighted amalgamation of a range of baseline adjustment factors assisted in the prediction of post-commissioning end uses for the Pimpama Coomera dual reticulated region. The predictive model indicated that recycled water end uses would account for 53 litres per person per day or 30.6% of total household consumption. The paper concludes with a brief overview of Phase 2 of the study which aims to compare actual post-commission end uses with the baseline situation and prediction, as well as the development of a robust end use model for dual reticulated regions.